Governments may be over-estimating global coal reserves, says US engineer

Peak oil has been much in the headlines recently, but whilst the world’s supplies of coal are substantially greater they may not be as extensive as governments believe, according to David Rutledge, a professor of engineering at the California Institute of Technology.

Ironically, Rutledge says, our shift to mechanised as opposed to hand coal mining has meant that coal seams which might have been exploited using 20th century techniques are no longer accessible – and hence no longer economically viable – with 21st century machines.

He estimates economically recoverable coal reserves at around 400 billion tons worldwide, as compared with government estimates of between 850 and 998 billion tons.

This is hardly a cause for celebration, however: Pushker Kharecha, a researcher at the NASA Goddard Institute for Space Studies warned that even 400 billion tons was enough coal to ‘push us past the threshold beyond which we would not want to go with the climate’.